1964 Quarter Pattern - P-5365, INCO

Coin Details

Description

Experimental clad quarter pattern P-5365, a second Pollock-cataloged INCO test piece struck from Washington quarter dies on a different alloy composition from P-5340. The existence of multiple Pollock-numbered quarter compositions underscores the depth of INCO's experimental program for this denomination. The quarter dollar was arguably the single most important coin in the silver replacement study, given its dominant role in parking meters, pay telephones, laundromat machines, and transit fare boxes throughout the 1960s. A failure to find a suitable quarter replacement would have had immediate and visible consequences for daily American commerce. P-5365's alloy formulation was evaluated against the same rigorous criteria applied to all INCO test pieces: striking quality on the Washington portrait, surface appearance and color, resistance to corrosion and tarnishing, edge appearance of the clad layers, and electromagnetic signature. The gap between the Pollock numbers (P-5340 and P-5365) indicates these represent compositions from different points in INCO's experimental matrix, potentially testing substantially different approaches to achieving the required electromagnetic profile. The composition ultimately adopted — copper core with 75/25 copper-nickel cladding — achieved the remarkable feat of matching the electromagnetic signature of 90% silver closely enough that existing vending machines could accept the new coins without modification, a triumph of applied metallurgy that owed much to the systematic testing documented by pieces like P-5365.

Rarity Notes

R-7. Extremely limited production for Treasury evaluation. The practical importance of the quarter denomination gives these patterns special historical significance.

Cross References

Pollock P-5365. Part of the INCO/Medallic Art Company experimental clad coinage program for the U.S. Treasury, 1964.